The Genetics Core is designed to accomplish the following goals: (1) To continue to collect and store blood samples for genetic analysis from all participants in the Program Project. (2) To establish and maintain immortalized lymphoblast cell lines derived from blood samples from all participants in the Program Project, (3) To generate genotypic data for the apolipoprotein E (APOE) gene on all study participants, (4) To genotype other genetic risk factors associated with AD on all study participants, (5) To provide genotypes of the study participants to the Central Database of the Program Project so that it can be combined with other data (e.g., neuropsychological test scores, SPECT, MRI, fMRI data) to determine the relationship of genotype to these measures, and the contribution of genotype to predicting the development of AD among individuals at risk.